The present invention relates to a piezo-vibrator unit incorporated in a ceramic package.
A piezo-vibrator such as a crystal oscillator is employed in a crystal oscillation circuit which is inevitably required in an electronic timepiece. In the conventional crystal oscillation circuit, capacitors are discrete from the crystal oscillator device and are electrically connected to the crystal oscillator device. This increases the number of required elements and complicates manufacture of the crystal oscillation circuit.
Accordingly, an object of the present invention is to provide a crystal oscillator device suited for mass production.
Another object of the present invention is to provide a ceramic package for integrally incorporating a piezo-vibrator element and capacitors.
Still another object of the present invention is to provide a piezo-vibrator unit which is easily installed on a circuit board.
Other objects and further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. It should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
To achieve the above objects, pursuant to an embodiment of the present invention, a ceramic package is provided for installing a piezo-vibrator such as a crystal oscillator element therein. Capacitors are formed directly on the rear surface of the ceramic package through the use of multi-layer printing techniques. The upper surface of the ceramic package is covered by a glass plate to seal the piezo-vibrator.
In a preferred form, the entire electrode terminals for the piezo-vibrator element and capacitors are formed on the bottom surface of the ceramic package in order to facilitate the installation of the ceramic package on the circuit board.